Forget one-day sales – an all-American painting of Santa Claus could become the season’s priciest Christmas gift when it’s auctioned off in Midtown tomorrow.

Norman Rockwell’s “Extra Good Boys and Girls” – the famed illustrator’s depiction of jolly St. Nick plotting out his annual gift-giving journey – is expected to fetch between $2.5 million and $3.5 million, according to Christie’s New York.

“This is our high-end Christmas present for this season,” said Eric Widing, head of Christie’s American Paintings Department.

The oil-on-canvas piece, used for a December 1939 Saturday Evening Post magazine cover, is part of an auction featuring more than 215 lots of American works of art.

Christie’s believes that it has gathered the most valuable selection of American art for one auction and estimates that the final tally could hit more than $60 million.

Meanwhile, the public is invited for a free viewing today at Christie’s Rockefeller Plaza location from 10 a.m. to 2 p.m.

“You can see in one venue museum-quality art from [still-life painter] Raphaelle Peale in the early 19th century right up through Edward Hopper,” Widing said. “And I think there’s always something fun about the fact that they’re all for sale.”